For storing cigarettes, a variable-capacity store is interposed between a cigarette manufacturing machine and a packing machine to compensate for any difference between the number of cigarettes produced and the number packed.
Patent EP-0738478 describes a variable-capacity store of the “first in-first out” type, which comprises an endless conveyor having a conveying branch for transferring a continuous stream of cigarettes from an input station to an output station of the store, and a return branch extending from the output station to the input station. Each branch is coiled about a pair of rotary transmission members, normally vertical-axis drums, movable transversely with respect to each other; and each pair of transmission members is associated with an actuating device for varying the distance between the axes of the transmission members in the pair, and which is connected to the other actuator device to adjust the lengths of the two branches in complementary manner.
Though efficient, the above known store has proved unsuitable for use on cigarette packing plants, on account of its size and the number of moving parts and relative actuating devices.
U.S. Pat. No. 6,065,585 discloses a reservoir system for rod cigarettes and having a first-in, first out buffer conveyor with a variable capacity; the capacity of the reservoir is varied by moving a pair of guides toward or away from each other. The guides support a conveyor belt for cigarettes in a spiral fashion from a lower input level to a higher output level to compensate for temporary fiddefences in flow rates.
GB-A-1497340 concerns an apparatus for the synchronous running of processing units of production lines with continuous and/or intermittent product flow, particularly for the independently driven processing units of light source manufacturing lines. The latter may consist of at least two independently driven processing units arranged sequentially with respect to product flow in the production line, with an endless transport member, particularly a chain conveyor, driven without slip between the processing units and having a variable capacity of storing.